See discussion in PR 67 and implementation in #d5fa787.

The warnings plugin supports 2 types of tools/parsers:

• single tool/parser: The user needs to select the correct parser ID and the parser will only create issues for the correct file format. Other files are reported as error.
• multi tool/parser: The user needs to select a single parser ID and then several parsers (a group) will try to parse the file. The issues are then aggregated for all parsers.

We need to decide which approach is the best. From the users perspective the latter one is the best. But this means we need to detect from the contents of the file, which parser can handle it.